Incandescent electric lamp.



lo6 s4 CROfiEF NC-E PATENTED APR. 25, 1905.

H. G. PARKER. INGANDESOBNT ELECTRIC LAMP.

APPLICATION 'rnnn JULY 2, 1904.

25 M Q W,

A TTORN/i r.

N f X72 amount of light increases greatly with the inessary to employ atubing capable of withseasonal. o. PARKER,

INOANDESOENT ELECTRIC 'LAMP.

Patented April 25, 1905.

PATENT OFFICE.

OF NEW YORK, N. Y.

en's

SPECIFICATION forming part of Letters Patent Not-788,493, dated April25, 1905.

Continuation of Serial No. 201,643. filed April 6, 1904- Thilapplication filed July 2, 1904. Serial No. 216.043.

'1'!) (all whom it may concern..-

Be it known that I, Heuscum. O. PARKER, of New York, in the county ofKings and State of New York, have invented a new and ImprovedIncandescent Electric Lamp, of which the following is a full, clear, andexact deseription.

My invention relates to improvements in incandescent electric lamps; andthe object of my invention is to produce a practically indestructiblelamp which has a higher efliciency than the lamp in general use andwhich is likewise cheaper to manufacture.

My invention is especially intended to produce a lamp in which theincandescent material is arranged in the core formed inside of arefractory translucent tube and in which the incandescing material israised to a heat sufficient to melt any kind of glass. As the crease ofheat, to produce a bright light in lamps of high resistance a state ofheat is required which is so much higher than that necessary to melt themost refractory glass that if an attempt is made to heat the resistingmatter in a glass tube the latter almost instantly slags and renders thelamp useless. It has been discovered, however, that quartz tubing hasthe transparent effect of glass and that it will stand the most intenseheat to which a contained resisting-body is subjected in producingalight of high efiiciency, and it is necstanding (without slagging) theintense heat indicated. 1 have found, further, that if the tube isessentially straight the resisting-bod y can be packed in powdered orgranulated form so closely that'there is little chance of combustion.

In the drawings I have shown the parts greatly exaggerated in order thatthe construction can be understood; but in practice I use a refractorytranslucent or transparent tube, preferably of very small bore and of anature to withstand a heat suflicient to slag glass. in this I packclosely a resisting-body, such as a stable oxid like thorium oxid orcarborundum, and at the ends of the tube 1 pack graphite or some betterconductor, so that the terminals may connect with this conductor and notbe unduly heated. With the resisting matter 1 also incorporatesuflicientgraphite to cause the current to pass through it, but notsuflicient to reduce resistance too much. Obviously the end portions ofthe lamp should 5 5 be of less resistance than the body portion,- sothat the terminals may not be affected and that the body part will givean efficient light.

With these ends in view my invention consists of an incandescentelectric lamp the construction of which will be hereinafter describedand the novel features claimed.

Reference is to'be had to the accompanying drawings, forming a part ofthis specification, in which the letters and figures representcorresponding parts in both the views.

Figure 1 is a longitudinal section of a simple form of lamp embodying myinvention;

- and Fig. 2 is a similar view. but showing the resisting part 7 effectof crystallization of the of the lam p. The tube 10 is preferably, and Ibelieve necessarily, of quartz, as 1 have found that this resistsperfectly the high heat of the body portion 11 of the lamp, and it hasthe necessary light-permeable qualities. It is possible that arefractory non-conducting lightpermeable tube can be made of othermaterial; but the essential thing is to have the tube capable ofwithstanding a heat higher than that required to slag glass. 1 havetried many kinds of 'glass to see if any efiicient results could beattained with it; but as glass melts at approximately 1,5200 Fahrenheitand the heat required to produce a lamp of 5 high efliciency is vastlyhigher than this it is obvious that the use of glass is out of thequestion. I am aware also that certain forms of crystals have been usedfor producing a lamp, the crystals having channels in them in 9 which aconductor is laid; but this is impractical, first, for the reason thatsuch a lamp is enormously expensive, and, second, that it is impracticalto keep out the oxygen.

In producing my lamp the tube has the resisting-body 11, preferably of astableoxid such as described, with a small percentage of graphitemingled with it hammered intothe tube, so that it is packed as tightlyas possible. In order to secure the results desired, it is importantthat the materials forming the core be treethat is, that they have nobinder by which the materials are stuck together. Hence the term free inthis connection will be understood as meaning independent particleswhich are not united by a binder. At the ends of this portion 11 I placegraphite 12 or other conductor. Behind this 1 pack asbestos 13 to holdthe powder in place. Before packing the asbestos, however, the terminalsa. of the wires A are embedded in the graphite, and then after theasbestos is in position the ends of the tube are sealed, as at 14. Anysuitable cement having the proper coefiicient of expansion and thenecessary elasticity can be used for this purpose. I have usedcarborundum with asuitable binder, such as silica or waterlass.

'l'lie particular iorm of connection 15 not essential; but it isessential that the wires have an excellent contact with the graphite 12.

When the current is turned on, the resistance offered by the bodyportion 11 causes the latter to be quickly raised to a high heat, andconsequently the lamp is made bright instantly. 1 find that there arepractically no chemical changes, and so far my experiments have shownmerely a slight crystallization, as indicated at 15, on the innersurface of the tube 10; but this takes place at the first heating anddoes not in any way impair the subsequent efiiciency of the lamp.

Having thus fully described my invention,

1 claim as new and desire to secure by Letters Patent 1. In an electriclamp, a highly-refractory non-conducting tube, permeable tolight,aconductive but resisting core of free particles tightly packedwithin the tube, the ends of the core offering less resistance tocurrent than the intermediate portion thereof, and circuitterminals heldin the end portions of the tube.

2. An electric lamp comprising a tube of quartz, a tightly-packedresisting but conductive core of free particles within the tube, thesaid core being less current resistant at the ends than at the middleportion and circuitterminals connected with the end portions of thecore.

3. An electric lamp comprising a tube of quartz, a conductive butresisting filling of free particles tightly packed in the tube, thefilling at the ends of the tube ofiering less resistance to acurreutthan the filling in the intermediate portion of the tube andsuitable terminals connected to the said conductors.

4. An electric lamp comprising a tube of quartz,a conducting butresisting filling of free particles in the tube, the said fillingcomprisingastable oxid with asmall percentage of graphite. the fillingnear the end portions of the tube containing a greater percentage ofgraphite than the filling in the intermediate portion of the tube,suitable conductors having their ends embedded in the filling at theends of the tubes, and suitable seals for inclosing the ends of thetube. 5. An electric lamp comprising a tube of quartz, a conducting butresisting filling of free particles in the tube, the said fillingcomprising a stable oxid with asmall percentage of graphite, the fillingnear the end portion of the tube containing a greater percentage ofgraphite than the filling in the intermediate portion of the tube,suitable conductors having their ends embedded in the filling at theends of the tubes, packing at each end of the filling and suitable sealsfor inclosing the ends of the tube.

6. An electric lamp comprising a tube of quartz, a conducting butresisting filling of free particles in the tube, the said fillingcomprising a stable oxid with a small percentage of graphite, thefilling near the end portion of the tube containing a greater percentageof graphite than the filling in the intermediate portion of the tube,suitable conductors havingv their ends embedded in the filling at theends of the tubes, asbestos packing at each end of the filling andsuitable seals for inclosing the ends of the tube.

HERSCHEL C. PARKER.

Witnesses:

W. B. HUICHINSON, JOHN T. CAROLAN.

